Laminated rock can delaminate and fail under certain stress states. Delamination-caused roof fall and cutter roof failure is a common failure mechanism in roadways in Pittsburgh coal seam due to the existence of laminated shale roof. Two-dimensional numerical models were developed at laboratory scale based on the bonded particle method in order to simulate the delamination with particle flow code. In these models, an assembly of bonded particles and parallel weak planes represents the laminated rock. This model calibrated the micro-parameters of the bonded particle material and weak planes with laboratory data. The mechanism of fracturing and delamination in a laminated specimen was investigated using unconfined and confined compression test and unsupported roof compression test. The numerical results show that, under a constant horizontal stress, delamination occurs when the stress is much lower than its compressive strength. The confined compressive test indicates that delamination is restrained by applying confining stress since delamination-caused failure does not occur during any stage of the confined compressive test. Unsupported roof compression tests showed propagation of cutter roof failure with initiation of cracks and delamination at the intersections of the roof and ribs. An outer failed zone and inner failed zone form separately. The separated zones connect and form an opening in the roof. The presented numerical results provide additional insight into process of delamination.

中文翻译：

---

实验室规模层状岩石分层的离散元建模

层状岩石在某些应力状态下会分层并失效。由于层状页岩顶板的存在，分层引起的顶板倒塌和刀具顶板破坏是匹兹堡煤层巷道常见的破坏机制。二维数值模型是基于结合粒子方法在实验室规模开发的，以使用粒子流代码模拟分层。在这些模型中，粘合颗粒和平行弱平面的组合代表了层状岩石。该模型使用实验室数据校准了粘结颗粒材料和弱平面的微观参数。采用无侧限和有限制压缩试验以及无支撑顶板压缩试验研究了层状试件的破裂和分层机理。数值结果表明，在恒定水平应力下，当应力远低于其抗压强度时，就会发生分层。受限压缩测试表明，由于在受限压缩测试的任何阶段都不会发生分层导致的破坏，因此通过施加限制应力来抑制分层。无支撑顶板压缩试验表明，在顶板和肋条的交叉处出现裂纹和分层，切割器顶板失效会蔓延。外部失效区和内部失效区分别形成。分离的区域连接并在屋顶上形成一个开口。所呈现的数值结果提供了对分层过程的进一步了解。受限压缩测试表明，由于在受限压缩测试的任何阶段都不会发生分层导致的破坏，因此通过施加限制应力来抑制分层。无支撑顶板压缩试验表明，在顶板和肋条的交叉处出现裂纹和分层，切割器顶板失效会蔓延。外部失效区和内部失效区分别形成。分离的区域连接并在屋顶上形成一个开口。所呈现的数值结果提供了对分层过程的进一步了解。受限压缩测试表明，由于在受限压缩测试的任何阶段都不会发生分层导致的破坏，因此通过施加限制应力来抑制分层。无支撑顶板压缩试验表明，在顶板和肋条的交叉处出现裂纹和分层，切割器顶板失效会蔓延。外部失效区和内部失效区分别形成。分离的区域连接并在屋顶上形成一个开口。所呈现的数值结果提供了对分层过程的进一步了解。外部失效区和内部失效区分别形成。分离的区域连接并在屋顶上形成一个开口。所呈现的数值结果提供了对分层过程的进一步了解。外部失效区和内部失效区分别形成。分离的区域连接并在屋顶上形成一个开口。所呈现的数值结果提供了对分层过程的进一步了解。